Materialism

Materialism, the denial of the existence of any substance except matter, and of any force except what is derived from the eternal properties of matter and from the motions of material bodies, molecules, or atoms. This doctrine involves the negation of the ideas of "soul" and "spirit "and of "deity" (except on a pantheistic hypothesis), and the explanation of mental phenomena in terms of chemical and mechanical change. One of the earliest materialists of western antiquity was Thales of Miletus, while Leucippus, Democritus, and Epicurus taught divers forms of atomic materialism; but these ancient philosophers did not entirely reject the gods of Greek mythology.